combinatorial.md

Person Greetings

Given person with Username, First Name, Last Name:

• It: Greets with first and last name if both are present. E.g. "Hello, Mickey Mouse"
• It: Greets with username if first or last name is missing (or both). E.g. "Hello, admin"

Sample Based Tests

Tests: uses first and last name if both are present

#	First Name	Last Name
1	Mickey	Mouse

Tests: Uses username if first or last name is missing (or both)

#	First Name	Last Name
1	null	null
2	Mickey	null
3	null	Mouse
4	""	""
5	Mickey	""
6	""	Mouse
7	" "	" "
8	Mickey	" "
9	" "	Mouse
10	null	""
11	null	" "
12	""	null
13	""	" "

Randomized Tests

Tests: uses first and last name if both are present

#	First Name	Last Name
1	Mickey	Mouse

Tests: Uses username if first or last name is missing (or both)

#	First Name	Last Name
1	Mickey	sample("", " ", null)
2	sample("", " ", null)	sample("", " ", null, "Mouse")

Resume

See example in JUnit + Datagen

Bonuses that you get from randomization:

• Faster to write and easier to maintain (1 or 2 instead of 13)
• Better coverage. Few people would cover all 13 cases, so better to have 1 randomized test than 1 sample based test.
• Much faster test runs (again because we reduced the number of tests). This is especially visible when running Component or System tests.

Be careful replacing full combinatorial testing with randomization:

• Critical parts of the app still need to be covered with full combinations. Otherwise you may miss something during this run but not the other
• Use your IDE to repeat the tests N times when first writing randomized tests and when changing parts that may break. In IntelliJ it's Edit Configuration of your test and then change Repeat option. This works with JUnit only as for 09/2016.